Re: smart fans
On Sunday, August 22, 2021 09:41:59 AM tomas@tuxteam.de wrote:
> On Sun, Aug 22, 2021 at 09:03:51AM -0400, Polyna-Maude Racicot-Summerside
> > Like I already wrote, modifying voltage doesn't change speed of a motor
> > (fan).
>
> I disagree. The thing poses [1] as a DC motor (2 pins power, one tacho).
> I don't think you get too much control over RPM, but putting the tacho
> in the control loop should be possible.
+1. A voltage controlled DC (computer fan) motor can be controlled /
regulated down to about 40% of full rated speed (depending on the motor). A
PWM (computer fan) motor can be controlled down to about 20% of full rated
speed.
> I have no idea what the motherboard/fan manufacturers actually do, though.
I know that at least some motherboards (perhaps only older ones?) controlled
fan speed via voltage control.
> [1] I'm nearly certain it's a BLDC in disguise, with some electronic goo.
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